1. Field of the Invention
The present invention relates generally to conveyor belts made from a plurality of longitudinally spaced rods coupled with interlocking links. More particularly, the present invention relates to conveyor belts utilizing buttonless rods.
2. Description of Related Art
Conveyor belts are popularly used in a number of different industrial fields to provide continuous motion of goods during manufacture, shipping, and other processes. Industrial conveyor belts generally include a series of spaced apart rods connected via a series of interlocking links which are welded to the rods. For the manufacture of small items, the rods may be covered with a fabric, plastic, or metal overlay, such as a mesh, to prevent the small items from slipping between the rods and falling to the manufacturing floor. A typical conveyor belt 10 is shown in FIG. 1, which corresponds to FIG. 1 of U.S. Pat. No. 5,954,188, which is incorporated herein by reference. Conveyor belt 10 includes rods 20 connected by links 22 covered by a mesh 14. A buttonhead 32 is formed on the ends of rods 20 to act as a stop for links 22. A weld is also typically formed between buttonhead 32 and link 22 for a stronger and more secure connection between rods 20 and links 22.
The buttonhead configuration on the ends of the rods of a conveyor belt can create challenges in maintaining the conveyor belt and associated equipment. For example, if a conveyor belt is subjected to a curvy path, the conveyor belt is driven around a curve via friction between the edge of the conveyor belt and a driving belt. The driving belt includes a grip surface which frictionally grasps the sides of the links of the conveyor belt to force the conveyor belt to follow the path of the curve. Such grip surfaces are typically made from materials such as plastics or rubber. Because the rod buttonheads protrude significantly from the outer surface of the link, the grip surface is not able to cleanly grab onto the flat surface of the leg of the link. The buttonheads also abrade the grip surface as the buttonheads move over the grip surface. Over time the grip surfaces of the driving belt are worn and damaged by the buttonheads more quickly than if the driving belt were to contact the leg of the link or a lower profile rod end. Therefore, having a conveyor belt without buttonheads could reduce wear on the driving surface.
Furthermore, in the manufacture of food products, the ability to clean equipment is an issue of paramount importance, so that the manufacturing plant remains sanitary so as not to contaminate the food products. In order to be able to clean a conveyor belt effectively, the number of small crevices and protrusions on the belt capable of trapping food are preferably minimized. As shown in FIGS. 1 and 2, the protrusion of buttonhead 32 from the outer surface of link 22 creates a point for the accumulation of debris. While weld material may be used to fill the space between buttonhead 32 and link 22, welds are typically bridge welds and formed only over a portion of buttonhead 32. As such, a buttonhead configuration increases the difficulty of maintaining a properly sanitized manufacturing system. Therefore, eliminating the buttonhead from the conveyor belt design would be advantageous in the long-term ability to keep the conveyor belt properly cleaned.
Additionally, while the buttonhead is useful during manufacturing by acting as a natural stop for links prior to welding the links in position, forming the buttonhead on the ends of the rods may actually result in increased manufacturing time. Rods are typically elongated steel members having ends of uniform diameter so that the links may slide easily onto the ends of the rods. To form the buttonhead, typically an electrode is touched to the end of the rod. The electrodes apply energy sufficient to melt and deform the end of the rod into the bulbous buttonhead. The melting of the rod material in this fashion releases carbon from the steel which accumulates on the buttonhead. The next processing step in the manufacture of the conveyor belt should be to weld the buttonhead to the side of the link. However, the carbon residue inhibits a good weld between the buttonhead and the link. Therefore, the carbon residue is generally cleaned off of the buttonhead prior to welding, for example with an acid bath. Eliminating the processing steps of forming the buttonhead and cleaning the buttonhead could provide significant savings in manufacturing time and complexity.
Therefore, there exists a need in the art for rod-and-link conveyor belts made without buttonheads.